The present invention relates to a panel fastener employed for connecting and fastening side wall panels or the like of prefabricated large-sized refrigerators or freezers.
In the conventional panel fastener disclosed in Japanese Utility Model Publication No. 12310/1978, a relief recess formed in a part of the inner peripheral surface of a cam-receiving hole of a hook plate and a spring-mounting recess formed in a part of the outer peripheral surface of an eccentric cam are aligned with each other for mounting a C-shaped leaf spring in a free state, and then, the eccentric cam is rotated 45 degrees in a specific direction in order to allow a circular portion of the leaf spring to slip out of the relief recess and bring the leaf spring into resilient contact with the circular inner peripheral surface of the cam-receiving hole. In the panel fastener thus assembled, when the side edge of the end portion of the hook plate is brought into contact with a pin provided to the mate panel, an eccentric projecting shaft of the eccentric cam is on an extension of a segment of a line connecting the pin and the center of the eccentric cam with each other, and rotating the eccentric cam further 180 degrees in the specific direction causes the hook plate to be pulled toward the panel concerned by double the eccentric distance, thereby allowing the hook part formed at the end of the hook plate to tightly engage with the pin.
In this panel fastener, however, the eccentric cam is adapted to be rotatable 360 degrees with respect to the hook plate. Therefore, if the eccentric cam is rotated more than 180 degrees, the hook plate is undesirably advanced toward the mate panel, causing the engagement between the hook part and the pin to be loosened, so that it is impossible to connect and fasten the panels to each other. Moreover, in the case where the eccentric shaft of the eccentric cam is not on the extension of the segment of the line connecting the pin and the center of the eccentric cam with each other when the side edge of the end portion of the hook plate is brought into contact with the pin, since the eccentric cam has been rotated in the direction opposite to the above-mentioned specific direction with respect to the hook plate, even if the eccentric cam is rotated 180 degrees in the specific direction, the hook plate cannot be satisfactorily pulled back toward the panel concerned. Accordingly, it is absolutely impossible to establish a tight engagement between the end hook part of the hook plate and the pin.